Tube reducing apparatus



April 8, 1969 D. L. LOMBARD TUBE REDUCING APPARATUS Sheet Filed July 15,1965 I N VENTOR. DAN! L L. LOMBARD M K/ ATTORNEY April 8, 1969 D.LOMBARD 3,436,944

TUBE REDUCING APPARATUS Filed July 15. 1965 Sheet or s INVENTOR. DANIELL. LOMBARD ATTORNEY A ril 8, 1969 D. LOMBARD TUBE REDUCING APPARATUSFiled July 15, 1965 REVOLUTIONS Fig. 7

m s |i| r oo m 50 H n w AOQ ..|||I 00 1 8 HM w 9 A8 m m2: ii, Fir O m wo Pwmw51u m TUBE ADVANCE DIE SET REVOLUTIONS REVOLUTIONS INVENTOR.DANIEL L. LOMBARD ATTORNEY Fig.9

April 8, 1969 D. L. LOMBARD TUBE REDUCING APPARATUS Sheet Filed July 15.1965 INVENTOR DANIE L. LOMBARD BY A/ ATTORNEY United States US. Cl.72208 3 Claims ABSTRACT OF THE DISCLOSURE This patent discloses tubereducing apparatus of the kind in which the tube is successively workedby a plurality of equiangularly spaced circular planetary diescontaining tapering die openings. The dies traverse a straight lineportion of substantial length while in contact with the work. Pinionsassociated with the ends of the dies cooperate with an internallytoothed endless gear path to insure proper indexing, i.e., to insurethat the wider part of the tapering groove in each die first comes intocontact with the tube, and at the same time, cam means are provided tocooperate with the dies while they traverse the straight line portion oftheir travel (while they are in contact with the work) to insure contactbetween the pinions and the gear path.

This invention relates to tube reducing apparatus, and more particularlyto tube reducing apparatus employing a plurality of opposed circulardies for continually reducing the diameter and wall thickness of metaltubing by the application of a cold swaging action.

Opposed circular dies have heretofore been employed for reducing tubing.Each of these dies has a tapering, semicircular, spiral-shaped grooveformed in its periphery. The circumferential length of the groovesalmost always is less than 180 When the dies are placed one on top ofthe other, the grooves define the circular path which contracts when thedies are moved along a linear path and simultaneously rotated inopposite directions; and which enlarges when the direction of travel ofthe dies is reversed.

Apparatus is available wherein a single pair of the opposed dies isemployed for reducing the outer diameter and wall thickness of metaltubing. This pair of dies is reciprocated, that is, moved back andforth, along a linear path of travel having a predetermined length.During the working stroke, the pair of dies is moved in one directionand affects a reduction in the tube size. At the end of the workingstroke, the entire die mass is stopped, after which the direction oftravel of the dies is reversed so that the dies are moved back towardthe starting point. The entire die mass is again stopped at the startingpoint and the direction of travel reversed. Before the second workingstroke, the tubing is advanced incrementally through the apparatus sothat a fresh section of tubing is positioned to be reduced.

Tube reducing apparatus of this type performs satisfactorily in reducingtubing. However, apparatus of this type has certain disadvantages whichthe present invention seeks to overcome.

For example, the dies are actually reducing tubing for only a fractionof each cycle of operation. It would appear on the surface that the workperformance of the dies is about 50% of each cycle. However, this is notthe case. During the working stroke of each reciprocal cycle ofoperation, the dies are initially accelerated from a dead stop andthereafter decelerated to a dead stop. During the acceleration and thedeceleration of the dies, the rate of work performed, on the average, isless than the rate of work performed by the dies when the dies reach thedeatent C 3,436,944 Patented Apr. 8, 1969 ice sired velocity. Hence,during each working stroke, the overall average rate of work performedis less than the rate of work performed by the dies when the dies reachthe desired velocity. Furthermore, the return stroke of each operatingcycle represents a complete loss in that no work is performed. Stillfurther, the tube cannot be advanced through the apparatus during thereturn stroke. The tube can only be advanced after the dies have beenstopped at the starting point of the working stroke or sufficient strokeprovided so that the dies can be rotated to a position where they losecontact with the material being reduced long enough to allow the tube tobe advanced before starting its return stroke.

Another disadvantage is that the reversing motion of the dies, subjectsthe various drive components to undesirable stresses. Consequently, thephysical size of this type of apparatus is large in order that thevarious stresses may be accepted and tolerated.

Still another disadvantage is that tube reducing apparatus of this typemust, of necessity, incorporate a reversing drive mechanism. Reversingdrive mechanisms are expensive to purchase and operate, as well as beingcomplicated and relatively difficult to maintain.

Accordingly, as an overall object, the present invention seeks toprovide tube reducing apparatus which does not have the above describeddisadvantages.

Another object of the invention is to provide tube reducing apparatuswhose production rate is higher than the production rates of any of thetube reducing apparatus heretofore available.

Still another object of the invention is to provide tube reducingapparatus employing rotating dies, wherein a greater percentage of thedie circumference is used for reducing tubing.

A further object of the invention is to provide tube redncing apparatusof novel construction wherein the mating, rotating dies move in a singledirection and at a constant speed.

A still further object of the invention is to provide tube reducingapparatus employing a plurality of mating, rotating dies all of whichmove at a constant speed and in a single direction.

Another object of the invention is to provide tube reducing apparatus bywhich the desired reduction in tube size may be accomplished by each setof mating, rotating dies.

Still another object of the invention is to provide tube reducingapparatus wherein the desired reduction in tube size may be accomplishedin multiple steps.

In accordance with the present invention, a tube reducing apparatus isprovided comprising a loading conveyor by which tubing is fed along alongitudinally feed axis of the apparatus; a tube reducing mechanism ofthe invention for reducing the outer diameter and wall thickness of thetubing; and a discharge conveyor by which the reduced tubing is conveyedto storage or to a further processing area. The tube reducing mechanismcomprises groups of planetary dies which revolve about separate axes ofrevolution which are perpendicular to the longitudinal feed axis of theapparatus. Each group of planetary dies is provided with means forguiding the dies thereof along an endless path of travel including astraight path segment positioned adjacent to and parallel with thelongitudinal feed axis of the apparatus. The sets of planetary dies arerevolved in timed relation about their respective axes of revolutionwhereby corresponding dies of the groups are brought opposite oneanother for movement along the straight path segments as a tube reducingdie set. Each tube reducing die set causes the desired amount ofreduction to be accomplished in a given section of the tubing. As theplanetary dies of each tube reducing die set moves along its endlesspath of travel, rotating means provided therealong causes the planetarydies to rotate about their central axes at equivalent angularvelocities. Hence, at any given moment in the travel of the tubereducing die sets, the planetary dies thereof will have the sameorientation. The present tube reducing mechanism also includes amechanism for rotating the tube about the longitudinal feed axis and foradvancing the tube incrementally along the longitudinal feed axis andhence through the apparatus.

As will hereinafter become apparent, the present tube reducing mechanismhas two modes of operation. As explained above, each planetary dieincludes a tapering, arcuate, spiral-shaped groove in its periphery.Consequently, the grooves of all of the tube reducing die sets may be sodimensioned that each tube reducing die set provides the same amount oftube reduction. In this instance, the tube advancing mechanism isoperated after the passage of each tube reducing die set. Alternatively,the grooves of each tube reducing die set may be so dimensioned wherebythe required amount of tube reduction is accomplished in multiple steps,that is, by a plurality of tube reducing die sets. In this instance, thetube advancing and rotating mechanism would be operated after a givennumber of the tube reducing die sets have completed their travel alongthe straight path segment.

The above and other objects and advantages of the present invention willbecome apparent from the following detailed description by reference tothe accompanying drawings, in which:

FIGURE 1 is a plan view of the tube reducing apparatus of the invention;

FIG. 2 is a side view of the tube reducing apparatus of the invention;

FIG. 3 is a cross-sectional view, taken along the line III-III of FIG.2, illustrating the planetary die assemblies of the invention;

FIG. 4 is a cross-sectional view, taken along the line IVIV of FIG. 3,further illustrating the planetary die assemblies of the invention;

FIG. 5 is a view schematically illustrating the path of travel of theplanetary dies of the invention;

FIG. 6 is a fragmentary cross-sectional view illustrating the reductionof a tubing by a die set of the invention;

FIG. 6A is a cross-sectional view taken along the line VI-AVIA of FIG.6;

FIG. 7 is a graphic illustration of one method of operating the presenttube reducing apparatus;

FIG. 8 is a graphic illustration of an alternative method of operatingthe present tube reducing apparatus;

FIG. 9 is a graphic illustration of a further alternative method ofoperating the present tube reducing apparatus;

FIG. 10 is a cross-sectional view, similar to FIG. 4, illustrating analternative embodiment of the present tube reducing apparatus; and

FIG. 11 is a cross-sectional view, taken along the line XIXI of FIG. 10;

TUBE REDUCING APPARATUSGENERAL DESCRIPTION Referring now to FIGS. 1 and2, there is shown a tube reducing apparatus indicated generally by thenumeral 20. The apparatus includes a feed conveyor 22 which conveystubing 24 along a longitudinal feed axis 26 of the apparatus 20. Thetubing 24 is conveyed into a tube reducing section 28 and thereafteronto a discharge conveyor 30 which accepts and conveys the reducedtubing 24a to a storage section or to a further processing area.

The tube reducing section 28 includes a tube reducing mechanism 32 shownin dotted outline in FIG. 2, which resides within a housing 34.Associated with the tube reducing mechanism 32 is drive means 36comprising a main drive motor 38 and a gear reducer 40. A pair of driveshafts 42 (only one visible) extends from the gear reducer and isconnected to the tube reducing mechanism 32, as will be explained. Alsoassociated with the tube reducing mechanism 32 is a tube advancing androtating mechanism 44 (shown in phantom outline) which rotates thetubing 24 about the longitudinal feed axis 26 and also advances the tubeincrementally along the longitudinal feed axis 26 and hence through thetube reducing mechanism 32.

As illustrated in dotted outline in FIG. 1, additional tube reducingmechanism 32 may be driven by the drive means 36. Alternatively,separate drive units may be provided for each additional tube reducingmechanism 32.

TUBE REDUCING MECHANISM 32 Referring now to FIGS. 3 and 4, the tubereducing mechanism 32 comprises two planetary die assemblies 46A and4613 which are of identical construction but of different orientationwith respect to the longitudinal feed axis 26. Each of the planetary dieassemblies 46A and 468 includes groups of planetary dies 48 whichrevolve about an axis of revolution 50 in opposite directions asindicated by the arrows 52. In the present tube reducing mechanism 32each group of planetary dies 48 consists of three circular dies 54A, 54Band 54C. The arrangement is such that corresponding circular dies, thatis, the dies 54A, the dies 54B and the dies 54C, of the planetary dieassemblies 46A and 46B, cooperate as a tube reducing die set during theactual tube reduction operation. As can be seen in FIG. 4, the circulardies 54A of the die assemblies 46A and 46B are positioned opposite eachother and cooperate to reduce the tubing 24. As the die assemblies 46Aand 46B rotate in opposite directions as indicated by the arrows 52, thecircular dies 54B will be positioned opposite each other to form asecond tube reducing die set and thereafter the circular dies 54C willbe positioned opposite each other to form a third tube reducing die set.

Each of the circular dies 54A-54C are rotatably supported on a carriage56 having a rod 58 projecting radially toward the axis of revolution 50and slideably engaged in a cylindrical arm 60 of a yoke 62. The yoke 62is rigidly secured to a shaft 64 which is rotatably supported in thehousing 34. Each of the shafts 64 is, in turn, coupled with and drivenby one of the drive shafts 42.

Each of the circular dies 54A, 54B and 54C, the carriages 56 and the'associated components thereof are identical in construction.Consequently, the following description of the components associatedwith the circular die 54A applies equally as well to the circular dies54B, 54C.

As can best be seen in FIG. 3, the circular die 54A is supported on ashaft 66 which projects outwardly of the carriage 56 and is rotatablysupported thereon. Secured at each extreme end of the shaft 66 is afollower 68. Secured to each end of the shaft intermediate of thecarriage 56 and the follower 68 is a pinion 70. Hence, the circular die54A has associated therewith two spaced followers 68 and two spacedpinions 70, all of which are rotatable with the circular die 54A aboutits central axis 72.

Referring again to FIGS. 3 and 4, each of the followers 68 is engageablein sequence with the inner surfaces of an arcuate cam 74, first andsecond inclined cams 7 6, 78 and the exterior surface of a horizontalcam 80. As best shown in FIG. 4, the first and second inclined cams 76,78 extend tangentially from the opposite ends of arcuate cam 74. Thefirst inclined cam 76 guides the followers 68 into engagement with thehorizontal cam 80. As the fol lowers leave the horizontal cam theyengage the second inclined cam 78 and are guided thereby to the arcuatecam 74. Accordingly, the followers 68 will be guided by the cams 74, 76,80 and 78 along an endless path of travel represented by a dash-dot lineconsisting of an arcuate path portion 74A corresponding to the arcuateshape of the cam 74, to inclined straight path segments 76A and 78Acorresponding to the inclined earns 76, 78, and a horizontal straightpath segment 80A corresponding to the horizontal cam 80. The arcuate cam74, the first and second inclined cams 76, 78 and horizontal cam 80 thuscomprise means for guiding the circular dies 54A-54C along an endlesspath of travel including the straight path segment 80A disposed adjacentto and parallel with the longitudinal feed axis 26 of the apparatus 20.The horizontal cams 80 have a second function, which is maintaining thecircular dies engaged with the tubing 24 during reduction of the same.

As stated above, the planetary die assemblies 46A and 46B are rotated inunison and in opposite directions. They are, however, rotated in a timedrelation whereby corresponding circular dies are brought opposite oneanother for movement along the straight path segments 80A as a tubereducing die set. Simultaneous with the revolution of the planetary dies54 about their respective axes of revolution 50, each of the circulardies is rotated about its central axis 72. To accomplish the rotation ofthe circular dies, gear means 82 is provided which comprises an arcuategear segment 84, inclined gear segments 86 which are tangent to the endsof the arcuate gear segment 84 and a horizontal, central straight gearsegment 88. The gear means 82 provides means for rotating thecorresponding planetary dies of each tube reducing die about theircentral axis 72 and at equivalent angular velocities. Consequently, atany moment in the movement of the circular dies 54 about the axis ofrevolution 50, the corresponding dies of each tube reducing die set willhave identical orientations.

The overall arrangement of the tube reducing mechanism 32 is such thatthe planetary dies 54 are simultaneously rotated about their centralaxis 72 and revolved about their axis of revolution 50 at a constantvelocity. Therefore, there is no acceleration or deceleration associatedwith the movement of the circular dies 54 as in the prior-art apparatus.

Reference is now directed to FIG. 5 wherein the movement of the circulardies 54 is schematically illustrated. The circular dies 54A, comprisingthe first tube reducing die set, move along the straight path segment80A from the dotted outline position to the dash-dot outline posiiondesignated by 54A. The planetary die assemblies 46A, 46B will haverevolved through an angle indicated at W when the circular dies 54A areat the position indicated by 54A. Meanwhile, the circular dies 54B movefrom the dotted outline position to that position illustrated by thedash-dot outline indicated at 54B. From the position indicated at 548',the circular dies 54B must move through an angle indicated at I in orderto reach the position previously occupied by the ircular dies 54A.

It should be evident that the angle W represents the work angle and theangle I represents the idle angle. As can be seen, the work angle W isless than the idle angle I. In one embodiment of the invention, thecircular dies 54A-54C were equiangularly spaced at 120 about the axis ofrevolution 50. The work angle W was about 50 while the idle angle I wasequal to about 70 Consequently, for each one-third of a revolution ofthe planetary die assemblies 46A and 46B, work is accomplished 42% ofthe time. Although the 42% figure seems low, it should be rememberedthat the circular dies 54A-54C are continuously revolved about the axisof revolution 50 at a constant angular velocity rather than beingreciprocated as in prior-art devices. Another important advantage whichshould be evident at this time, is that since the circular dies 54A-54Cof the planetary die assemblies 46A and 46B rotate at a constant angularvelocity, the present tube reducing mechanism 32 may be connecteddirectly to the gear reducer 40 whose sole function is to reduce therelatively large number of revolutions per minute of the main drivemotor 38 to a speed commensurate with the needs of the tube reducingmechanism 32. Consequently, the present tube reducing mechanism 32 doesnot have and does not require a reversing drive mechanism as does theprior-art tube reducing apparatus described above.

Referring now to FIGS. 6 and 6A, there is illustrated a pair of opposedcircular dies each designated generally by the numeral 54. It is to beunderstood that the following description applies equally as well to allof the circular dies 54A-54C.

As can be seen, the opposedl circular dies 54 rotate in the directionsindicated by the arrows 94 and move along the straight path segments Ain the direction indicated by the arrows 96. As is conventional, each ofthe circular dies 54 is provided with a semicircular groove 98 extendingaround a fraction of its periphery. The groove 98 is tapered having thelargest diameter at the point 100 and having the smallest diameter atthe point 102. Beyond the point 102, that is to the point 104, thediameter of the semicircular groove is constant. Consequently, theoverall arrangement is such that when the points 100 of the circulardies 54 are opposite one an other, a circular pass of largest diameteris defined. As the circular dies move to the right of FIG. 6, thecircular pass formed diminishes in diameter until the points 102 of thecircular dies 54 are opposite each other at which time the diameter ofthe circular pass is at a minimum. Continued rotation of the circulardies 54 to the right of FIG. 6 provides a circular pass of constantdiameter corresponding to the circular pass defined by the semicirculargroove 98 between the points 102 and 104.

As can be seen, the tubing consists of three regions, namely, the region24 corresponding to the unreduced tubing supported on the feed end ofthe apparatus; the reduced end 24a which is at the desired diameter andwall thickness and is supported on the discharge end of the apparatus;and a tapered section 24b whose diameter and wall thickness vary fromthe point indicated at X to the point indicated at Y. Beyond the pointindicated at Y the wall thickness and outer diameter of the taperedsection 24b is constant and extends to the point indicated at Z. Duringrotation of the circular dies, the point 100 thereof will coincide withthat point on the tubing indicated at X while the point 102 of thecircular dies corresponds to that point on the tapered section 24bindicated at Y. Furthermore, that section of the semicircular groove 98between the points 102 and 104 of the circular dies corresponds to theregion of the reduced end 24a indicated between the points Y and Z.Consequently, between the points X and Y on the tapered section 24b, thetubing is being reduced in outer diameter and in wall thickness. Betweenthe points Y and Z, however, the outer diameter and wall thicknessremains constant. The point indicated by Y is known in the art as thesizing point while the region between the points Y and Z is known as theironing section.

As can be seen, a mandrel 106 is supported Within the tapered section24b of the tubing 24 in the region of the straight path segments 80A.The mandrel 106 is station ary and comprises a tapered portion 108 and asize point 110 extending through and beyond the region defined by thepoints Y and Z. The tapered portion 108 of the mandrel 106 supports thetubing during its reduction in outer diameter and wall thickness, whilethe sizing point 110 supports the constant diameter segment (between thepoints Y and Z) of the tubing so that the reduced section 24a will havethe desired outer diameter and wall thickness.

As explained above, the circular dies of prior-art tube reducingapparatus had semicircular grooves whose circumferential length was lessthan In one specific example of a prior-art circular die, the workingsurface of the semicircular groove had a circumferential length of about118 angular degrees. At each end of the working face of the semicirculargroove, there was provided a contour-relief consisting of a semicirculargroove having a diameter larger than the unreduced diameter of thetubing. Similarly, at the smallest diameter end of the semicirculargroove there was provided a second contourrelief consisting of asemicircular groove whose diameter was larger than the diameter of thereduced tubing. The overall circumferential length of the semicirculargroove including the contour-relief end segments was 180.

In the present apparatus, the circular dies revolve about their axis ofrevolution in one direction, for example, the counterclockwise directionillustrated in the drawings. Consequently, the circumferential length ofthe semicircular grooves 98 may be greater than 180. Furthermore, nocontour-relief segments are necessary. Therefore, a maximum amount ofthe circumferential length of the circular die may be employed in theactual reduction of tubing. For example, in one embodiment of thepresent invention, the circumferential length of the semicircular groove98 between the point 100 and the point 104 consisted of about 200angular degrees.

It should be evident then that since a. greater circumferential lengthof the circular die may be employed in reducing the tubing, the distancebetween the points X and Z is greater than the corresponding distance inpriorart tube reducing apparatus. It follows then that for the samereduction in outer diameter, the angle of taper in the present tubereducing apparatus is shallower than the corresponding angle of taper inthe prior-art tube reducing apparatus. Therefore, in the present tubereducing apparatus the reduction of the tubing is more easilyaccomplished than in the prior-art apparatus.

MODE OF OPERATION Inasmuch as the present tube reducing mechanism 32employs a plurality of planetary dies, it has many modes of operation.The present tube reducing mechanism has hereinabove been described andillustrated as including three planetary dies for each of the planetarydie assemblies 46A, 4613. Consequently, three tube reducing die sets areformed as the planetary dies are revolved about their respective axes ofrevolution 50.

One mode of operating the present tube reducing mechanism 32 isgraphically illustrated in FIG. 7 wherein the tube reducing die sets areindicated by tangent circles designated A, B and C. The graph of FIG. 7is a plot of the per cent of tube reduction accomplished by each die setversus revolutions of the die assemblies. In this instance, thesemicircular grooves of each tube reducing die set A, B and C, isdimensioned so as to provide the same amount of tube reduction.Consequently, as can be seen in FIG. 7, each of the tube reducing diesets A, B and C will provide 100% of the desired tube reduction. Therefore, the tubing may be advanced after each of the tube reducing diesets A, B and C has traversed the straight path segment 80A. Tubeadvance is indicated in FIG. 7 by the vertical arrows 109. Inasmuch asthe circular dies of each tube reducing die set is immediatelydiseangaged from the tubing at the end of the straight path segment 80A,the tube may be advanced automatically immediately after thedisengagement. The time required to advance the tubing will, of course,be considerably less than the time required for the second tube reducingdie set to traverse through the idle angle I (FIG. and therefore thetime involved in advancing the tubing does not add to the total timerequired for one-third of a revolution of the present tube reducingmechanism 32. Consequently, when the second tube reducing die set isbrought into engagement with the tubing, the tubing is already advancedand is in position for the second tube reducing operation.

A second mode of operation is graphically illustrated in FIG. 8, whichalso is a plot of the percent of tube recluction accomplished by each ofthe tube reducing die sets revolutions of the die assemblies. As in FIG.7, each of the tube reducing die sets is indicated by tangent circlesindicated by the letters A, B and C while the tube advance points areindicated by the arrows 109. In this instance, the semicircular groovesof the first tube reducing die set A are dimensioned to provideapproximately one-third of the desired tube reduction; the semicirculargrooves of the second tube reducing die set B are dimensioned to provideapproximately two-thirds of the desired tube reduction; and thesemicircular grooves of the third tube reducing die set C aredimensioned to pro- Cir vide 100% of the desired tube reduction.Consequently, and as illustrated in FIG. 8, when the first tube reducingdie set A has traversed the straight path segment A, the tubing willhave been reduced approximately one-third of the desired tube reduction.When the second tube re ducing die set B has traversed the straight pathsegment 80A, the tubing will have been reduced approximately two-thirdsof the desired reduction. Finally, when the third tube reducing die setC has traversed the straight path segment 80A, the tubing will have beenreduced of the desired tube reduction. Hence, the tubing is reduced inmultiple steps. In this instance, the tube is advanced after eachcomplete revolution of the planetary dies about the axis of revolution,as indicated by the arrows 109.

It should be noted at this time that the tube reducing mechanism 32 ofthe present invention may be provided with more than three planetarydies and therefore modes of operation other than those described arepossible. For example, FIG. 9 is a graphic illustration of analternative embodiment of the present tube reducing mechanism whereinfour tube reducing die sets are provided. The tube reducing die sets areillustrated in FIG. 9 as opposed, tangent circles labeled A, B, C and D.The graph of FIG. 9 is similar to the graphs of FIGS. 7 and 8. In thisinstance, the semicircular groove of the first tube reducing die set Ais dimensioned to provide approximately one-half of the desired tubereduction while the semicircular grooves of the second tube reducing dieset B are dimensioned to provide 100% of the desired tube reduction.Similarly, the semicircular grooves of the third tube reducing die set Care dimensioned to provide approximately one-half of the desired tubereduction While the semicircular grooves of the fourth tube reducing dieset D are dimensioned to provide 100% of the desired tube reduction.Consequently, in the operation of this embodiment the tube will bereduced in multiple steps by the first and second tube reducing die setsA and B, whereupon the tube is advanced as indicated by the arrow 109.Thereafter, a second multiple step reduction is accomplished by thethird and fourth tube reducing die sets C and D, whereupon the tube isagain advanced. Consequently, after each half revolution of the tubereducing mechanism, the tube is advanced incrementally along thelongitudinal feed axis of the apparatus.

TUBE REDUCING MECHANISMALTERNATIVE EMBODIMENT Reference is now directedto FIGS. 10 and 11, wherein an alternative embodiment of the tubereducing mechanism is illustrated. Corresponding numerals will beemployed to identify corresponding parts heretofore described.

In this embodiment, a tube reducing mechanism 32 is provided comprisingtwo planetary die assemblies 114A, 114B. Each of the die assemblies114A, 114B includes groups of planetary dies 48 which revolve about anaxis of revolution 50 in the direction indicated by the arrows 52. Eachgroup of planetary dies 4-8 includes three circular dies 54A, 54B and54C. Each of the circular dies 54A- 54C is rigidly connected to a shaft66 supported for rotation by a carriage 116 having a rod 118 projectingradially inwardly toward the axis of revolution 50. A drive member 120is supported for rotation about the axis of revolution 50. The rods 118are slideably supported on the drive member 120 for movement therewithabout the axis 50 and for sliding movement radially thereof. Centrallywithin the drive member 120 there resides a stationary shaft 122 havinga cam 124 rigidly secured thereto. Rotatably supported at the end ofeach of the rods 118 is a cam follower 126 which engages the peripheryof the cam 124.

At each end of the shaft 66, there is secured a pinion 70. The pinion70, the shaft 66 and the circular die 54 associated therewith arerotatable about the central axis 72 of the circular die. Disposed aboutthe axis of revolution 50 of each of the planetary die assemblies 114A,

114B are two spaced gear means 82 each comprising an arcuate gearsegment 84 whose opposite ends terminate in inclined gear segments 8-5,86 and a horizontal, central straight gear segment 88 connected to theends of the inclined gear segments 85, 86. The pinions 70' mesh with thegear means 82.

In this embodiment, the gear means 82 have their straight gear segments88 resting one on top of the other rather than being staggered as in theembodiment illustrated in FIG. 3. Hence, this embodiment is more compactthan is the embodiment illustrated, for example, in FIG. 3.

Connected to each of the drive members 120 is a drive shaft 128 which,in turn, is connected to the gear reducer (not shown here). As can bestbe seen in FIG. 11, the shafts 122 supporting the cams 124, have one endkeyed to a plate member 130 extending between both of the shafts 122 andhave their other ends journaled to the drive shafts 128.

In operation, the drive shafts 128 rotate the drive members 120 which,in turn, revolve the planetary dies 54A, 54B and 54C about the axis ofrevolution 50. The pinions 70 meshing with the gear means 32 providerotation of the circular dies 54A-54C about their central axis 72. Eachof the circular dies 54A-54C traverses an endless path of travelindicated by a dash-dot outline consisting of an arcuate path segment74A corresponding to the arcuate gear segment 84, inclined path segments76A, 78A corresponding to the inclined gear segments 85, 86 and ahorizontal straight path segment 80A corresponding to the horizontal,central straight gear segment 88.

tThe shafts 122 supporting the cams 124 are stationary and, therefore,the cams 124 remain in the positions illustrated. The cams 124 have thesame general peripheral configuration as the endless path of travelindicated by the dash-dot line described above. However, each of thecams 124 includes a concave cam surface 132 positioned opposite thestraight path segments 80A. The contour of each of the concave camsurfaces 132 corresponds to the path of travel of the cam follower 126as each of the carriages 11 6 moves from an inclined position when thecentral axis 72 of the shaft 66 is coincident with a point 134 on thestraight path segment 80A to the oppositely inclined position whereinthe central axis 72 of the shaft 66 is coincident with a point 136 atthe end of the straight path segment 80A. The overall arrangement ofthis embodiment is such that the circular dies 54A-54C are revolvedabout their respective axis of revolution 50 while simultaneously beingrotated about their central axis 72. Consequently, the correspondingcircular dies 54A-54C of each of the planetary die assemblies 114A, 114Bare brought sequentially opposite one another for movement along thestraight path segments 80A as a tube reducing die set, as describedabove.

Although the present invention has been shown in connection with certainspecific embodiments, it will be readily apparent to those skilled inthe art that various changes in form and arrangement of parts may bemade to suit requirements without departing from the spirit and scope ofthe present invention.

1 claim as my invention:

1. In apparatus for reducing at least the outer diameter of a tubing,the combination comprising: groups of planetary dies, the planetary diesof each group being equiangularly spaced about an axis of revolution;the axes of revolution of said groups of planetary dies residing in acommon plane and being equidistant from a longitudinal feed axis of saidapparatus and perpendicular thereto; means for each group of planetarydies for guiding the planetary dies of said groups along separateendless paths of travel about their respective axis of revolution, eachof said paths of travel including a straight path segment positionedadjacent to and parallel with said longitudinal feed axis; means forrevolving said groups of planetary dies in timed relation about theirrespective axes of revolution whereby corresponding planetary dies ofsaid groups are brought opposite one another for simultaneous movementalong said straight path segments as a tube reducing die set; means forrotating the corresponding planetary dies of each tube reducing die setabout their central axes during movement thereof along said endlesspaths of travel; and means for rotating and advancing a tubeincrementally along said longitudinal axis and hence through saidapparatus; a number of said tube reducing die sets being dimensioned toreduce a tube in multiple steps, said tube rotating and advancing meansbeing operable only after the passage of said number of said tubereducing die sets along said straight path segments.

2. In apparatus for reducing tubing, the combination comprising:planetary die assemblies having axes of revolution which are equivalentfrom a longitudinal feed axis of said apparatus and perpendicularthereto; each of said planetary die assemblies comprising a drive memberrotatable about the axis of revolution, a plurality of planetary diesequiangularly spaced about said drive member and hence the axis ofrevolution, means for connecting said planetary dies to said drivemember, means for slideably supporting each of said planetary dies formovement radially of the axis of revolution, at least one endless geartrack adjacent to said planetary dies, said endless gear track having astraight segment positioned adjacent to and extending parallel with saidlongitudinal feed axis, a pinion secured to each of said planetary diesand engaged with said endless gear track, said pinions causing rotationof the planetary dies about their respective central axes duringrevolution of said planetary dies about the axis of revolution, and cammeans for maintaining the pinions engaged with said endless track insaid straight segment thereof and comprising a cam member supported atthe axis of revolution, and a cam follower associated with eachplanetary die; means connected to the drive members for revolving saidplanetary dies in timed relation whereby corresponding planetary dies ofsaid assemblies are brought opposite one another for simultaneousmovement along said straight segments as a tube reducing die set; andmeans for rotating and advancing a tube incrementally along saidlongitudinal axis and hence through said apparatus.

3. In apparatus for reducing tubing, the combination comprising:planetary die assemblies having axes of revolution which are equidistantfrom a longitudinal feed axis of said apparatus and perpendicularthereto; each of said planetary die asemblies comprising a drive membersupported for rotation about the axis of revolution, a plurality ofplanetary dies equiangularly spaced about said drive member and hencethe axis of revolution, means for connecting each of said planetary diesto said drive member for movement therewith about the axis ofrevolution, means for slideably connecting each of said planetary diesto said drive member for movement radially of the axis of revolution,spaced, parallel, endless gear tracks each having a straight gearsegment disposed adjacent to said longitudinal feed axis and extendingparallel therewith, said planetary dies being positioned between saidspaced, parallel, endless gear tracks for movement therebetween, apinion secured to each side of each planetary die, said pinions beingengaged with said endless gear tracks whereby revolution of saidplanetary dies about the axis of revolution causes rotation of theplanetary dies about their respective central axes, a cam followerassociated with each planetary die and rotatable about the central axisof the die, and at least one straight cam segment inwardly spaced fromand parallel to each of the straight gear segments of said endless geartracks, said straight cam segments being positioned for engagement bythe cam followers during movement thereof along the straight gearsegments whereby said pinions are maintained engaged with said straightgear segments; means connected to the drive members for revolving saidplanetary dies about their axes of revolution and in timed relationwhereby corresponding planetary dies of said assemblies are broughtopposite one another for simul- 1 1 taneous movement along said straightgear segments as a tube reducing die set; and means for rotating andadvancing a tube incrementally along said longitudinal feed axis andhence through said apparatus.

References Cited UNITED STATES PATENTS 350,857 10/1886 Anderson 72-1911,013,429 1/1912 Nowak 72-215 1 2 6/ 1912 Reinhard 72-215 6/ 196 1Nowakowski 72--208 CHARLES W. LANHAM, Primary Examiner.

5 L. A. LARSON, Assistant Examiner.

US. Cl. X.R.

